Source games

Source is a 3D game engine developed by Valve Corporation. It debuted in June 2004 with Counter-Strike: Source and shortly thereafter Half-Life 2. Other games using the engine include the physics sandbox Garry's Mod, first-person action RPG game Dark Messiah of Might and Magic, the first-person puzzle game Portal, first-person beat-em-up Zeno Clash and the MMORPG Vindictus developed by Nexon.

Modularity and notable upgrades

Source was created to evolve incrementally as technology moves onwards, as opposed to the backwards compatibility-breaking "version jumps" of its competitors. With Steam, Valve can distribute automatic updates with new versions of the engine among its many users.

In practice however, there have been occasional breaks in this chain of compatibility. The release of Half-Life 2: Episode One and The Orange Box both introduced new versions of the engine that could not be used to run older games or mods without the developers performing upgrades to code and, in some cases, content. But both times the work required to move from the older version to the newer was significantly less than what one might have come to expect from other engines - as was demonstrated in 2010, when Valve updated all of their core Source games to the very latest engine build.

High dynamic range rendering (2005, Day of Defeat: Source)

Simulation of a camera aperture and the ability to fake the effects of brightness values beyond computer monitors' actual range. Required all of the game's shaders to be rewritten.

Soft particles (2007, Orange Box)

An artist-driven, multiprocessor-optimized particle system. Unlike most such systems, particles are not 'clipped' by 3D geometry.

Hardware facial animation (2007, Orange Box)

Hardware accelerated on modern video cards for "feature film and broadcast television" quality.

Multiprocessor support (2007, Orange Box)

A large code refactoring allowed the Source engine to take advantage of multiple CPU cores on the PC, Xbox 360 and Playstation 3. On the PC, support was experimental and unstable until the release of Left 4 Dead. Multiprocessor support was later backported to Team Fortress 2 and Day of Defeat Source.

Xbox 360 support (2007, Orange Box)

Valve created the Xbox 360 release of The Orange Box in-house, and support for the console, unlike support for the PlayStation 3, is fully integrated into the main engine codeline. It includes asset converters, cross-platform play and Xbox Live integration.[20] Program code can be ported from PC to Xbox 360 simply by recompiling it.

Mac OS X support (2010)

Starting in April 2010, Valve has announced the availability of OpenGL rendered Left 4 Dead, Left 4 Dead 2, Team Fortress 2, Counter-Strike: Source, Portal, Day of Defeat: Source, and the Half-Life series on Mac OS X. All future Valve games will be released simultaneously for PC and Mac.[22][23] Games will only use Direct3D on Windows, and only OpenGL on the other platforms.

Valve has stated an intent to move Left 4 Dead's AI Director technology into the engine proper,[24] but there is no evidence that this has yet taken place.

In 2009, Left 4 Dead 2 introduced support for Squirrel scripts to be executed in maps.[25] It exists to automate changes to the behavior of existing C++ objects, but cannot extend the game's compiled code.

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2Counter-Strike Source: computer game, multiplayer team first-person shooter developed by Valve and Turtle Rock Studios; remake of Counter-Strike, modified in 1999 for the game Half-Life.

3CS Promod: first professional modification for Counter-Strike Source, c all the same gameplay, which we are so accustomed to the Counter-Strike 1.6.

4Half-Life Deathmatch Source: reissue cult game Half-Life in 1998 on the basis of a better game of the Source engine with a number of innovations in graphical performance and gameplay.

5Adrenaline Gamer 2: Multiplayer modification of Half-Life 2 Deathmatch, focused on professional players, similar to Adrenaline Gamer on the engine GoldSource.

6Left 4 Dead: Multiplayer computer games in the genres of first-person shooter and survival horror, set up studio Turtle Rock, which since January 10, 2008 became part of Valve Corporation.

7Left 4 Dead 2: The computer game, the cooperative first-person shooter with elements of survival horror, developed by Valve Corporation and published by Electronic Arts. The game is an independent sequel to Left 4 Dead.